noun. Any of several large sea ducks, especially of the genus Somateria of northern regions, having soft, commercially valuable down and predominantly black and white plumage in the male.

noun. Same as eiderduck.

noun. Same as eider-down.

noun. Any species of sea duck of the genus Somateria, esp. Somateria mollissima, which breeds in the northern parts of Europe and America, and lines its nest with fine down (taken from its own body) which is an article of commerce; -- called also eider duck. The American eider (S. Dresseri), the king eider (S. spectabilis), and the spectacled eider (Arctonetta Fischeri) are related species.

noun. Down of the eider duck, much sought after as an article of luxury.

noun. Any of the species of the genera Polysticta or Somateria, in the seaduck subfamily Merginae, which line their nests with fine down (taken from their own bodies).

noun. duck of the northern hemisphere much valued for the fine soft down of the females

"Iceland, there is a bird called the eider duck, which is much valued on account of the soft and beautiful down which grows upon its breast, and is used for pillows and counterpanes, being wonderfully light, warm and elastic."